1,538 research outputs found
Integrable Boundaries, Conformal Boundary Conditions and A-D-E Fusion Rules
The minimal theories are labelled by a Lie algebra pair where
is of -- type. For these theories on a cylinder we conjecture a
complete set of conformal boundary conditions labelled by the nodes of the
tensor product graph . The cylinder partition functions are given
by fusion rules arising from the graph fusion algebra of . We
further conjecture that, for each conformal boundary condition, an integrable
boundary condition exists as a solution of the boundary Yang-Baxter equation
for the associated lattice model. The theory is illustrated using the
or 3-state Potts model.Comment: 4 pages, REVTe
Pion transition form factor at the two-loop level vis-\`a-vis experimental data
We use light-cone QCD sum rules to calculate the pion-photon transition form
factor, taking into account radiative corrections up to the
next-to-next-to-leading order of perturbation theory. We compare the obtained
predictions with all available experimental data from the CELLO, CLEO, and the
BaBar Collaborations. We point out that the BaBar data are incompatible with
the convolution scheme of QCD, on which our predictions are based, and can
possibly be explained only with a violation of the factorization theorem. We
pull together recent theoretical results and comment on their significance.Comment: 10 pages, 4 figures, 3 tables. Presented by the first author at
Workshop "Recent Advances in Perturbative QCD and Hadronic Physics", 20--25
July 2009, ECT*, Trento (Italy), in Honor of Prof. Anatoly Efremov's 75th
Birthday. v2 wrong reference tag removed. v3 Fig. 4 and Ref. [27] correcte
Hadronic Form Factors: Combining QCD Calculations with Analyticity
I discuss recent applications of QCD light-cone sum rules to various form
factors of pseudoscalar mesons. In this approach both soft and hard
contributions to the form factors are taken into account. Combining QCD
calculation with the analyticity of the form factors, one enlarges the region
of accessible momentum transfers.Comment: 12 pages, 3 figures, Talk at the Workshop "Shifmania, Crossing the
boundaries: Gauge dynamics at strong coupling", May 14-17,2009, Minneapolis,
USA; table entry and reference update
Video killed the interview star: Does picture-in-picture affect interview performance?
Although technology-mediated selection interviews have become more prevalent in practice, research on this phenomenon has failed to keep pace. One pressing need is to understand the dimensions upon which technology-mediated interviews might differ from one another. Particular aspects of synchronous video technology may negatively affect interviewees and those negative effects may be exacerbated by the evaluative nature of the interview. We explored this question by investigating the effects that one such aspect, the picture-in-picture window, has on interviewees. This study used a 2 (picture-in-picture vs. no picture-in-picture) x 2 (evaluative framing vs. non-evaluative framing) between-subjects experimental design to test the hypothesized relationships. We conclude that presence of a picture-in-picture window during a video interview did not directly affect interview performance or applicant reactions, but did increase cognitive load. This suggests that picture-in-picture technology affects interviewees in a potentially detrimental way. We discuss how research and practice should navigate these findings
Information on the Pion Distribution Amplitude from the Pion-Photon Transition Form Factor with the Belle and BaBar Data
The pion-photon transition form factor (TFF) provides strong constraints on
the pion distribution amplitude (DA). We perform an analysis of all existing
data (CELLO, CLEO, BaBar, Belle) on the pion-photon TFF by means of light-cone
pQCD approach in which we include the next-to-leading order correction to the
valence-quark contribution and estimate the non-valence-quark contribution by a
phenomenological model based on the TFF's limiting behavior at both
and . At present, the pion DA is not definitely determined, it is
helpful to have a pion DA model that can mimic all the suggested behaviors,
especially to agree with the constraints from the pion-photon TFF in whole
measured region within a consistent way. For the purpose, we adopt the
conventional model for pion wavefunction/DA that has been constructed in our
previous paper \cite{hw1}, whose broadness is controlled by a parameter . We
fix the DA parameters by using the CELLO, CLEO, BABAR and Belle data within the
smaller region ( GeV), where all the data are consistent
with each other. And then the pion-photon TFF is extrapolated into larger
region. We observe that the BABAR favors which has the behavior close
to the Chernyak-Zhitnitsky DA, whereas the recent Belle favors which
is close to the asymptotic DA. We need more accurate data at large region
to determine the precise value of , and the definite behavior of pion DA can
be concluded finally by the consistent data in the coming future.Comment: 6 pages, 5 figures. Slightly changed and references update
A Construction of Solutions to Reflection Equations for Interaction-Round-a-Face Models
We present a procedure in which known solutions to reflection equations for
interaction-round-a-face lattice models are used to construct new solutions.
The procedure is particularly well-suited to models which have a known fusion
hierarchy and which are based on graphs containing a node of valency . Among
such models are the Andrews-Baxter-Forrester models, for which we construct
reflection equation solutions for fixed and free boundary conditions.Comment: 9 pages, LaTe
Next to leading order eta production at hadron colliders
Inclusive eta production at hadron colliders is considered,based on
evaluation of eta fragmentation functions at next to leading order. Absolute
predictions at LHC and SSC are presented, including the ratio ,
together with the estimate of the theoretical uncertainty, as a possible
neutral background to the detection.Comment: 8 pages, latex, FNT/T-93/13,14 figures avilable upon reques
Chiral Anomaly Effects and the BaBar Measurements of the Transition Form Factor
The recent BaBar measurements of the transition
form factor show spectacular deviation from perturbative QCD prediction for
large space-like up to . When plotted against ,
shows steady increase with in contrast with the flat
behavior predicted by perturbative QCD, and at is
more than 50% larger than the QCD prediction. Stimulated by the BaBar
measurements, we revisit our previous paper on the cancellation of anomaly
effects in high energy processes , and apply our results to the
transition form factor measured in the
process with one highly virtual photon. We find that, the transition form
factor behaves as and produces a striking agreement with the BaBar data
for with which also reproduces very well the
CLEO data at lower .Comment: v4, LaTeX, 8 pages, one figure, minor changes(references), to appear
in Int. J. Mod. Phys.
Conformal Field Theories, Graphs and Quantum Algebras
This article reviews some recent progress in our understanding of the
structure of Rational Conformal Field Theories, based on ideas that originate
for a large part in the work of A. Ocneanu. The consistency conditions that
generalize modular invariance for a given RCFT in the presence of various types
of boundary conditions --open, twisted-- are encoded in a system of integer
multiplicities that form matrix representations of fusion-like algebras. These
multiplicities are also the combinatorial data that enable one to construct an
abstract ``quantum'' algebra, whose - and -symbols contain essential
information on the Operator Product Algebra of the RCFT and are part of a cell
system, subject to pentagonal identities. It looks quite plausible that the
classification of a wide class of RCFT amounts to a classification of ``Weak
- Hopf algebras''.Comment: 23 pages, 12 figures, LateX. To appear in MATHPHYS ODYSSEY 2001
--Integrable Models and Beyond, ed. M. Kashiwara and T. Miwa, Progress in
Math., Birkhauser. References and comments adde
Moduli Stacks of Vector Bundles and Frobenius Morphisms
We describe the action of the different Frobenius morphisms on the cohomology
ring of the moduli stack of algebraic vector bundles of fixed rank and
determinant on an algebraic curve over a finite field in characteristic p and
analyse special situations like vector bundles on the projective line and
relations with infinite Grassmannians.Comment: 19 page
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